Process for recovering gasoline and other hydrocarbon liquids from natural gas



Aug; 1, 1933. w. G. LAIRD 1,920,941

PROCESS FOR RECOVERING GASOLINE AND OTHER HYDROCARBON LIQUIDS FROM NATURAL GAS Filed Jan. 5, 1927 BLENDED PRODUZ T M44751? D/STR/BUTOR cansoL/ms 1 477571 MAI J0 MqTER D/STR/BL/TOR COOL /N6 CO/L Patented Aug. 1,1933 l PATENT oFFicsI PROCESS FOR RECOVERING GASOLINE AND OTHER. HYDROCARBON LIQUIDS FROM 1 NATURAL GAS Wilbur G. Laird, NewYork, N. Y., assignor to Henry L. Doherty, New York, N. Y.

Application January 5, 1927. Serial No. 159,052

2 Claims.

This invention relates to a process for recovering gasoline or other hydrocarbon liquids from natural gas by absorption in oil absorbent.

In many processesheretofore used for absorbing gasoline from natural gas, the contact between the liquid absorbent and the gas has been obtained by causing the liquid to travel downwardly through a column of coke, brickwork or other porous material and causing the gas to pass upwardly through the column. The

purpose of the coke or brick work is to breakthe liquid into fine streams and thereby increase the surfaces at which absorption takes place. In this type of apparatus, however, it is practically impossible to obtain a uniform distribution of gas and liquid owing to variations in structure in oil or other liquid absorbing medium is diflicult or impossible to obtain. Also, with this type of apparatus, it is very difiicult to control the absorption of constituents which are present in very small quantities in the gas.

The primary object of the present invention is to provide a process in which a greater and more uniform contact surface between the gas and oil and in which a full control of the flow of gas and oil may be obtained.

Another object of the present invention is to provide a process of absorbing liquid hydrocarbons from gas by Which higher concentration and a more complete recovery of the liquid hydrocarbons may be obtained.

' higher boiling hydrocarbons may be separately recovered. h

The accompanying drawing shows an apparatus in which may be carried out a process emor any suitable vation of an apparatus for bodying the preferred form of the invention,- of which:

The figure is a diagrammatic view in end elerecovering gasoline from natural gas. a I

This application as to common subject matter is-a continuation of a pending application for apparatus for recovering gasoline or other hydrocarbon liquids from natural gas, Ser. No. 421,442, v

filed November 3, 1920, Patent No. 1,666,744 which in turn is a division of an application for process of and apparatus for recovering gasoline or other hydrocarbon liquids from natural gas Ser. No. 306,391 filed June 24, 1919, Patent 1,541,514.

The manner in which the oil vapors of natural gas are absorbed in the apparatus shown in the drawing constitutes an important feature of the present invention. This absorption is efiected by causing a thin film of absorbing oil to pass in a horizontal layer across the absorption chamber, and in causing fine streams of gas to pass upwardly through the layer of oil in such a way that the oil will be blown into a fine foam; As this oily foam advances across the absorption chamber additional streams of gas are passed through the foam so that the bubbles are broken up and reformed. In this Way the oil is held in the thinnest possible film and this film contacts on both sides with the gas to be treated. This insures that the gas and oil are intimately brought into contact over an enormous area.

The oil to be used as an absorbing medium for the hydrocarbon vapors in the gas will ordinarily be a petroleum oil fromwhich the naphtha and other lighter constituents have been distilled. However, any type of hydrocarbon oil, which is not saturated with naphtha and light hydrocarbons, may be employed, or crude oil itself' may be employed in this absorption. Any hydrocarbon vapors present in the gas, which can be 'maintained in a liquid condition at ordinary temperatures will be absorbed and is later recovered from the oil by distillation with rectification and partial reabsorption to form commercial grades of naphtha, gasoline and other light oils as more specifically pointed out hereinafter. 1

In treating gases, under high pressure, the apparatus should be as small and compact as possible in order that strength may be obtained without making the walls of the absorber excessively thick. Due to the efficient scrubbing action of the absorbing liquid'foam and the consequent short distance of travel of the absorbing liquid it is possible to use a horizontally arranged cylindrical container of comparatively small condenser 58 and, if desired, the proper liquid diameten 1 may be used to producea blended gasoline. Any

To separate the hydrocarbon vapors from natvapors which, are uncondensable under the conural gas with the apparatus shown in the draw ditions leave the bubbler 68 through a vent '74 5 ing, the natural gas under the line pressure enters and may be returned to the service main 18. 0

the bottom of an absorber 10, through apipe 12, From the description given above it is apparent where the gas passes through, and, comes in. conthat the absorption occurring in chambers 10 and tact with, a layer of absorbing oil to remove the '16 maybe carried out under considerable presmajor portion of the hydrocarbons.-- Fromthe-- sures. The pressure used in the pipes 34 and 38 10 absorber 10 the gas passes through a pipe 1% to as Well as in the still 40 is only sufiicient to over- 85 a second absorber 16 in which the gas passes come the liquidhead and resistance to flow in through, and comes in contactwith a freshlsup1 ui llifin l ubsequent parts of the apparatus. The ply of absorbing oil wherejall of,,theremaining;- pressure required is mainly that necessary to available hydrocarbon vapors in the gas are abovercome the. pressure head of the liquid in the sorbed. The gas freed f rom th e hydrocarbon heatexchangerfie and the resistance in the con- 90 vapors then passes from the absorber 16 through; densen- 58 .where vapors from the still 40 and a pipe 18 to a gas main. condenser'52 must pass in counter-flow and in The oil to be used asanabsorbingliquid is- -contact withcondensate flowing back down this drawn from a sump 20 through a. ,pip e 22 .-by condenser 58. In addition some pressure will be 20 means of a pump 24 and is forced through a pipe necessary to force light hydrocarbons not con- 95 6 -.,to,theabsorber 16. fieretheoil absorbsthe clensed.in;, th ev condenser 58 into the; oil to be hydrocarbon vapors remaining in the gas; after b1, 1 p e 68 a d-T70. v 1 passing'throughthe absorber 10. From the ,ab- 7 The yapors leaving the still 40 vare;composed of sorber ldthe oilpassesthrough apipe 28; tothe the ordinary natural gas hydrocarbons ot vary- 125 absorber 10 in which it meets a fresh supply of ingboiling points. These vapors first," pass 100 gasand; is further. saturated with hydrocarbon through air .cooledcondenser 52where some of vapors. The oil from the absorber 1Q then passes the heavier-hydrocarbons such, for.- example, as -through a pipe 30 to a pressure reducing'fioat. hexane which boils at 156 F., are condensed. valve 3 2; which serves to prevent gas from passing yThe remaining vapors enter-the rectifying'con- ..'3Q: through pipe 30. Fromthevalve 32 theoil under denser bfi which is cooledon the outside .with,.105

a,;low;.pressure flows through a pipe 3 1; into a watenfrom the pipe. 60. ,-In,thiscondenser ,the coil mounted in a heat exchanger 36.- In the heat rising vapors constantly enter cooler zones and exchanger 36 the ;oil is heated by; hot absprbent corne -into contact with condensate flowing-back oil which has been heated to drive 01?. hydl'ocardown the condenser so that certain parts of-,the .bon vapors previously absorbed -The-p which vapors are condensed while portions or the, con- =11O has been preheated in. the heat exchanger fifl densatetare revaporized and again carriedup, in thengpasses through a pipe38 to a stillO where. th condenser, V i j ilfi l h ate 'd i ut-th hydroca b n .Becauseor the fact that the gcondensationin vapo'rs ;From the still. 40 theabsorbent oil then the upper portion of the-condenseri58 is carried 414C! flowsjhrough a pipe 42to a pump 43- by which out at substantially normal pressure.andatthe;n15

.. it forced through the heat exchanger36 where normal temperature of the cooling water (501 to it gives up part of its heat tothe oil-passingto. 30 F.), it is evident that:hydrocarbons.collectthe still. .The cooled absorbent ,oilthen passes ing in the header 54 from thecondensersfiZand through a pipe 144 tobefurthercooled in acoil '58 will contain only such hydrocarbonsas iare 45 ,,46,which iscooledby aspray of wateriromthe condensible under these conditions which-,- ac-=:;

pipe 48.. The coldpilisthen-passed tothesump cording to the boiling points.wouldincludelpenorgstorage tank-.29 through a pipe; 59, provided 'tane (boiling point 97f F.) andhigher, boiling witha siphon breakbl; Thepumps 2 i and 43 .hydrocarbons but would not include butane beoperated by any suitable power transmit- (B. P. 34 F. or lower hydrocarbons in any sub- Q .t ing-.;h eoha m ep t -d g a m tica :stantial amountbecause of the successive con nl25 atg19. r e I densationsandrevaporizations;occurring asithe The hydrocarbon .vaporsset iree from t vapors from the still advance up the condenser 58. absorbing oilin the stillAOpass toan .-QQ The lighter hydrocarbons leavingatheycondenser condenser 52} in which, t eavy. vap r a :58 are blended vwith a suitable .oil intheabsorbers 1.1 5;, condensed, The n n e s P 'Y 'O the 68 ,andflotoformgasoline so that-substantially condenser ,52' .collect ;in a .manifold ..,54 .-,and .all of the more valuable constituents taken ,from pass through a. p'ipe.,56 to a conclenseri, 58 the natural gas by the absorbingymediurn in the which is..cooled by aispiay f. .watenirom a ;absorbers. ,l0 and 16 are converted.- into .com-

pipe .60. The condensed vapors. -from,the con-winercial products. v I p .r densers 52 and 158(co1lectinthe maniio1d..,54 .As 111 be recognized those skilled and flow through ap pe 62to al eting,.tank I art to which this invention pertains thegasoline 64., ,Frornthe tank 64 the condensed.vapors,may collected in the tank- 64 will be a relatively stable flow througha pipe 66 to a bubbler 68. ThQQQ product in comparison to the gasoline commonly ,..densate .;rises ,in .theibubblerg68 then. overflows obtained from natural gas Ordinary natural 5 through'a pipefili and passes toa second bubblel', gas gasoline usuallyvcomprises a mixture of. both :pncondensed vapors frorn the condenser;58,,.heavy and light hydrocarbons which is: difficult pass through a pipe '72 and enter the bubblrf70 to handle and keep in liquid form due to {its hav- .;under the suriace of the condensates. The vapor ing a higher vapor pressure thanthe, gasoline obthen passes through a pipe 73 into the condensate tained by theprocess described.above. J V in the bubbler 6 8 toremove the. last traces, of .While the process illustrating an-embodiment vapor from, .theJ-uncondensable, gas. Hydrocare. ofthe invention has been described in connection bonliquids which are not produeedinthe process withthe apparatusshownin the drawing it will, 1nay;=be;.used.inthe bubblers..68 and70 ,to,take nevertheless, be apparent to those familiar with ,up ,the lighter hydrocarbons whichgrnay be ab the art of .treatingnaturalgasfor-the recovery sorbed from the.uncondensed;.vaporsgfro n the or gasolinethat the processlmay-beparried out in' I Having thus described my invention, I

other apparatus or may be used with existing obsorbing or compressing plants for the recovery of a stable gasoline. I

claim:

1. In the process of producing natural gas gas: oline from natural gas, in which hydrocarbons from natural gas are absorbed bymeans of an absorbing medium, the improvement which com prises effecting the separation of said hydrocarbons from said medium by distillation, passing the vapors so produced through condensing zone in an air cooled condenser to effect a con-- 3 densation of a portion of the heavier hydrocarbons, passing the vaporsleaving said condenser into a separate condensing zone in an upright condensing unit whereby additional hydrocarbons are condensed, and mixing said condensates to produce said gasoline.

2. In the process of recovering from natural gas a mixture of natural gas hydrocarbons comprising a gasoline relatively stable under ordinary conditions of temperature and pressure and in which the natural gas is subjected to an ab sorbing medium to absorb hydrocarbons from said gas, the improvement which comprises distilling the absorbed natural gas hydrocarbons from said medium, passing the resulting vapors through a plurality of condensing zones of decreasing temperature in the direction of vapor l gasoline from said uncondensed gas and-vapor and thereby yield a blended gasoline product. WILBUR G. LAIRD. 

